<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
      <div class="input-num">
        <button @click="sub">
            -
        </button>
        <span>{{num}}</span>
        <button @click="add">
            +
        </button>
      </div>
      <img src="" alt="">
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var app=new Vue({
            el:"#app",
            data:{
                num:1
            },
            methods:{
                add:function(){
                    //console.log('add');
                    if(this.num<10){
                       this.num++;
                    }else{
                        alert('别点啦，最大啦');
                    }
                },
                sub:function(){
                    //console.log('sub');
                    if(this.num>0){
                       this.num--;
                    }else{
                        alert('别点啦，最小啦');
                    }
                }
            },
        })
    </script>
</body>
</html>